The present disclosure relates generally to computers. More particularly, the present disclosure relates to migrating a processing workload between different substantially identical hardware resources in a virtualized computing system.
Large computing platforms that are at the core of data centers and cluster configurations provide large database services, large web hosting services, large gaming services, virtual environments, enterprise management systems for governments, businesses, etc., are becoming more common. International Business Machine (IBM) continues to provide innovative solutions for these large computing platforms. A good computing system is not only robust but is easily maintainable. It can be appreciated that not all components of a server can be hot swapped. Thus, to provide maintenance on a piece of hardware acting as a server on a platform, at multiple times during its life the server must be removed from the platform for such servicing. To remove the piece of hardware from the platform without disrupting service, it is desirable to seamlessly move the processes operating on the hardware to a target piece of hardware. The alternate piece of hardware can be an alternate server or a target server where the target server can continue the process. After the hardware is removed from service problem solving, maintenance such as adding improvements and upgrading and replacing the entire server with a newer more advanced model can be achieved.
On current systems a hypervisor and other firmware can be utilized to create logical partitions (LPAR) where different LPARS can operate different operating systems. One feature that can facilitate a processes of moving a workload or a workload partition from hardware resource to hardware resource is code that is set up to operate as a workload partition. Accordingly an LPAR can be broken up into multiple WPARSs.
In some systems, workload partitions can be moved from resource to resource to further increase the efficiency of a large processing complex. This mobility of workload partitions (WPARs), was first made available in IBM operating system. The AIX® system is a name given to a series of proprietary operating systems based on a Unix OS sold by IBM, for several of its computer system platforms. Generally, mobile WPARs are WPARs that have characteristics that allow the workload partition to be moved or migrated from physical machine to physical machine, or from a source machine to a target machine.
AIX workload partitions (WPAR)s can be defined as operation of multiple virtualize operating systems that are operating within a single copy of the AIX operating system. As seen by most applications, each workload partition appears to be a separate instance of the AIX operating system. Such an appearance can occur within the partition, because the applications can have a private execution environment. The applications can be isolated in terms of process, signal and file system. Further, applications can have their own unique users, groups, and dedicated network addresses. Inter-process communication can be restricted to processes executing in the same workload partition. Accordingly, a WPAR can be transparent as most applications are unaware of the software creating the workload partition and thus most application can run, unmodified in a WPAR. In addition, workload partitions can be integrated with AIX resource controls and it can be possible to assign central processing unit (CPU) and/or memory shares to a WPAR. Yet further, workload partitions can establish limits on threads and processes.
As implied above, there are many advantages in migrating operating system instances across distinct physical hosts in data centers, clusters, etc. For example, workload migration allows a clean separation or isolation between hardware and software and facilitates fault management, load balancing, and low-level system maintenance. Carrying out migration while OSs continue to run provides a system administrator of data centers and cluster environments with a very useful tool, as long as there is only minimal interruption or minimal downtime. Live migration is very desirable and provides a practical tool for servers running interactive loads, for example, by moving a workload to different servers a hardware problem can be isolated to a particular server if faults only occur on a particular server.